Pass-through mounts used to support tubing associated with hydraulic, fuel, and other systems may be used in environments in which they are subjected to potentially hazardous, corrosive, and/or harsh environments such as aircraft fuel systems and/or other potentially difficult environments. One example is the use of pass-through rib mounts to support hydraulic and fuel lines within aircraft wing fuel tanks. Aircraft wing fuel tanks are a demanding environment in which to provide secure and reliable retention of tubing. In particular, the space to install mountings may be confined, potential ignition sources (e.g., due to electromagnetic effects such as arcing due to lightning strikes and static discharge due to fuel transfer) must be avoided, the fuel may be chemically aggressive, and the fuel may lubricate mountings. With respect to electromagnetic effects, components within an aircraft fuel tank must meet stringent aviation safety requirements to ensure that metal objects within the fuel tank are properly bonded, grounded and/or isolated.
Some commercial aircraft wings are substantially constructed of composite materials. The composite materials generally are less conductive than traditional, metal components. Further, composite wings may provide lesser electromagnetic shielding than traditional metal wings. The lesser shielding may lead to higher induced currents in internal components of the wing (such as metal tubing).
Composite wings may have greater structural flexibility (relative to traditional, metal wings) and thus may subject internal tubing and mounts to greater relative movement and/or stresses. Moreover, the greater flexibility of composite wings may make the wings more sensitive to loads applied to the internal tubing, including loads applied by misalignment of the tubing and the centerline of the pass-through mount assemblies.
Thus, there is a need for pass-through mounting assemblies which are designed to reduce electromagnetic effects, accommodate alignment of tubing, and/or permit tubing movement.